The umbilical stalk, vein, and arteries, urachal region, and urinary bladder of 9 healthy Holstein calves were scanned ultrasonographically at weekly intervals from 1 day to 3 weeks of age. Four additional calves of representative ages, 1 day, 1 week, 2 weeks. and 3 weeks were euthanatized after ultrasonographic evaluation of the umbilical structures. Umbilical structures from these 4 calves were dissected, photographed, and examined histologically to ensure normalcy. These gross specimens were correlated with the ultrasonographic images and compared with serial ultrasonograms of 9 calves. The ultrasonographic scanning technique and the appearance of normal umbilical stalk, arteries, and vein, and urachus in calves were different from those described for foals. The umbilical vein of calves was scanned from the umbilical stalk to the liver along the right abdominal wall. Two veins, which merged within the body wall, were identified within the stalk. Umbilical arteries were not found within the umbilical stalk; they ended abruptly near the apex of the urinary bladder. A urachal remnant was not identified in any of the calves. A range of normal values for measurement of the umbilical stalk, umbilical arteries, and umbilical vein at 3 sites was determined. The described ultrasonographic appearance and measurements of the normal Holstein calf umbilicus may be used as a reference for evaluation of calves with internal umbilical abnormalities.

The effect of a dietary supplement, choreito, on in vitro struvite crystal growth in feline urine was evaluated. Adult specific-pathogen-free cats (4 females, 4 males) considered to be clinically normal on the basis of physical examination findings and normal results of CBC, serum biochemical analyses, and urinalyses obtained before the beginning of the study were used. Before 24-hour urine sample collections were made, cats were fed a commercial canned diet with 0 or 500 mg of choreito supplement/kg of body weight for at least 2 weeks in a cross-over design with 4 cats/treatment. Filtered urine samples were analyzed for urine pH, specific gravity, osmolality, and urine electrolytes. The struvite activity product was calculated, using a statistical software program that calculates urine saturation. Urine samples were placed in wells of cell culture plates, increasing concentrations of ammonium hydroxide were added to adjacent wells to stimulate struvite crystal growth, and the plates were incubated at 37 C. Crystal growth was assessed by determination of number of crystals and supersaturation index by direct visualization, using an inverted microscope. Supplementation of the diet with choreito (at this concentration) did not change urine pH, specific gravity, osmolality, urine electrolyte composition, or calculated struvite activity product. However, supplementation significantly (P < 0.05) reduced crystal number and supersaturation index. These results indicate that direct observation of struvite crystal formation in whole urine may more accurately predict the effects of treatments to prevent or treat struvite urolithiasis than do calculations based on electrolyte concentration that do not account for the effect of urine macromolecules. It also may mean that choreito consumption affects the concentration of inhibitors or promoters in urine. It was concluded that choreito significantly (P < 0.05) reduced growth of struvite crystals in feline urine, and thus may have a role in prevention of feline struvite urolithiasis. In vivo studies will be necessary to test this hypothesis.

Bronchoalveolar lavage was performed through an endotracheal tube in 34 specific-pathogen-free cats to determine expected values for bronchoalveolar lavage fluid cytologic analysis, using this method of collection. Saline solution for lavage was instilled in 3 separate aliquots at a volume of 5 ml/kg of body weight each. Analysis of sequential aliquots was performed to investigate the differences in cell counts among the 3 fractions. The effect of combining aliquots, including or omitting the first fraction, was evaluated to determine whether all aliquots could be combined for analysis without substantially affecting results. The total number of nucleated cells retrieved from each cat ranged from 0.9 to 31.1 X 10(6). Most of these cells were macrophages (78 +/- 15%, mean +/- SD) and eosinophils (16 +/- 14%). The first aliquot had the greatest number of epithelial cells, and the lowest total nucleated cell count and relative and absolute eosinophil counts. Differences among aliquots also were identified for relative and absolute macrophage counts, relative and absolute neutrophil counts, and absolute lymphocyte count. Statistically significant differences were found for many of the cell counts when values from the combination of the second and third aliquots were compared with values from the combination of all 3 aliquots. Magnitude of the differences was small, and these differences were not believed to be of practical consequence.

Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (MSD) values and application of the established MSD values for diagnosis of cervical stenotic myelopathy (CSM). Variability in MSD determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The MSD of the vertebral canal was determined in 50 horses with CSM and 50 control horses, using a radiopaque marker method for correction of magnification. In addition, a ratio of the absolute MSD to the sagittal width of the vertebral body and a ratio of the absolute MSD to the length of the vertebral body were determined in 100 CSM-affected and 100 control horses. Response operating characteristic curve analysis of each method determined that the sagittal ratio method of canal diameter assessment provided the most accurate interpretation of cervical radiographs for diagnosis of CSM, with sensitivity and specificity of larger than or equal to 89% at each vertebral site. The accuracy of the ratio method, without consideration of bony malformation, supports the importance, and perhaps prerequisite, of generalized vertebral canal stenosis in the pathogenesis of CSM. Subjective evaluation of bony malformations from cervical radiographs of 100 CSM-affected horses and 100 control horses indicated that CSM-affected horses have more severe bony malformation than do control horses. However, moderate to marked degenerative joint disease of the articular processes was frequently observed in control horses. Subjective evaluation of bony malformation does not distinguish between CSM-affected and unaffected horses.

We used monoclonal antibodies and immunohistologic examination of lymph nodes, to elucidate the pathogenesis of lymphosarcoma induced by, infection with bovine leukemia virus (BLV). The superficial cervical lymph nodes from 3 BLV-infected but apparently healthy sheep and 5 sheep with full-blown lymphosarcoma were examined. We also investigated the integration of bovine leukemia provirus by use of Southern blotting. In lymph nodes from sheep lacking clinical signs of infection, in which the provirus had been integrated at multiple sites in the genome, many large hypertrophic follicles were observed in the cortex. These follicles had germinal centers consisting of CD4+T cells and B cells that expressed surface IgM (sIgM) and major histocompatibility complex (MHC) class-II antigens, but not B cell-specific B2 molecule. The percentage of CD4+T cells in the cortex was significantly (P < 0.05) higher than that of the controls and sheep with lymphosarcoma. In all sheep with lymphosarcoma, the lymph nodes were completely destroyed by proliferating neoplastic cells, and in addition, small atrophic follicles, which consisted of normal B-cell marker-positive cells, were seen near the trabecula and the subcapsule. In these instances, neoplastic cells appeared to be a monoclonal population derived from a single CD5- B-cell lineage and to be classified as 2 types, CD5-CD4-CD8-B2+MHC class-II+sIgM+ and CD5-CD4-CD8-B2+MHC class-II+sIgM-. Moreover, CD8+T cells infiltrated diffusely throughout the tumorous lymph nodes apart from the atrophic follicles, and CD4+T cells were observed around atrophic follicles. Both types of T cells were small-size, normal lymphocytes with round and noncleaved nuclei, and were apparently non-neoplastic cells. In fact, after separation by use of a panning method, it seems that, in blood mononuclear cells from BLV-infected sheep without clinical signs of infection, but in lymphosarcomatous stages, the proviral genome was integrated only in B cells and not in T cells. Thus, we conclude that the host's immune response may be still maintained at a lymphosarcomatous stage.

Bilateral osteochondral defects (10 mm2 X 3 mm deep) were created on the distal articular surface of the radial carpal bone of ten, 2- to 3-year-old horses. One defect of each horse was repaired, using a sternal cartilage autograft (treated), and the other was left untreated (control). The horses were exercised on a high-speed treadmill at incrementally increased speed and duration over the course of 12 months. Horses were evaluated arthroscopically at 6 to 7 weeks, and clinical examinations were conducted weekly at exercise. Twelve months after surgery, carpuses of each horse were radiographed and clinically examined prior to euthanasia. A gross pathologic evaluation of each joint was conducted, and samples were collected for histologic, histochemical, histomorphometric, and biochemical evaluation. Radiographically, the grafted joints had more extensive evidence of arthropathy, and clinically, 8 of the 10 horses were more lame in the grafted limb. On the basis of histomorphometry, the repair tissue of the grafted defects contained a greater median percentage of hyaline cartilage (45%) than that of control defects 4.5%), and the control defects contained a greater percentage of fibrocartilage (82%) than did grafted defects (28.5%). A greater median percentage of repair tissue stained with safranin-O in the grafted defects (24.5%) than in the control defects (3.5%). On gross pathologic and histologic evaluation, repair tissue of the control defects had better continuity and was more firmly attached to the subchondral bone than was repair tissue of the grafted defects. Repair tissue of the grafted defects had extensive fissure and flap formation. Histologically, subchondral bone reactivity and fibroplasia was extensive in grafted joints. Repair tissue of grafted defects had a greater percentage of type II collagen (mean sem, 83.5 +/- 2.95%) than did controls (mean, 79.4 3.87%) that was not statistically significant. Hexosamine content was significantly higher (P < 0.05) in repair tissue of the grafted defect (mean, 28.9 +/- 3.00 mg/g of dry weight) vs control (mean, 20.6 +/- 1.85 mg/g of dry weight). On the basis of this experimental model, sternal cartilage autografts cannot be recommended at this time for repair of osteochondral defects in athletic horses.

Influence of age, breed, and stage of pregnancy on hepatic ultrasonographic findings of cows was determined. In addition, the relation between body weight, height at the withers, milk production, and the measurements determined via ultrasonography was investigated. The liver of 186 cows was examined ultrasonographically. The cows comprised Swiss Braunvieh, Simmental, and Holstein breeds, and age ranged from 2.5 to 11.5 years. The ultrasonographic findings of the liver, gallbladder, caudal vena cava, and portal vein were described, and the position, size, thickness, and distal angle of the liver were determined. In addition, the position and diameter of the caudal vena cava and portal vein were determined. There was no significant difference between any of the variables determined and breed or age. Therefore, measurements for the 3 breeds and for the various ages were summarized into 1 group. There were significant correlations between body weight, milk production, and size and thickness of the liver. In 3 pregnant cows, the liver was examined ultrasonographically 8 times during the course of pregnancy. Positive correlation was detected between stage of pregnancy and diameter of the caudal vena cava. There was a negative correlation between stage of pregnancy and diameter of the portal vein. In 23 cows, the ultrasonographically determined measurements of the liver were compared with those determined at slaughter. Weight of the liver correlated well to thickness of the liver determined via ultrasonography.

Maximal conduction velocities of compound action potentials evoked by stimuli of 2 times threshold in the caudal cutaneous sural (CCSN) and medial cutaneous antebrachial (MCAN) nerves were determined by averaging potentials evoked and recorded through percutaneous needle electrodes. Mean maximal conduction velocities of compound action potentials were: CCSN = 61.3 +/- 2.0 meters/second (m/s) and MCAN = 56.4 +/- 2.8 m/s. To confirm accuracy of our percutaneous recordings, compound action potentials were recorded through bipolar chlorided silver electrodes from the exposed surfaces of fascicles of the CCSN and the MCAN. The maximal conduction velocities of these potentials were in agreement with the conduction velocities of compound action potentials that were evoked and recorded through percutaneous needle electrodes. The specificity of stimulating and recording sites was verified by recording before and after section of the nerves. Stimuli from 3 to 5 times threshold evoked a second, longer latency, compound action potential that consisted of a variable number of components in the CCSN and MCAN. The configurations and conduction velocities of the shorter latency potentials were the same as those of the single compound action potentials evoked by stimuli of 2 times threshold. Mean conduction velocities of the longer latency potentials were: CCSN = 24.4 +/- 2.6 m/s and MCAN = 24.5 +/- 2.2 m/s. Needle electrode and direct stimulation of either the CCSN or the MCAN at 3 to 5 times threshold failed to evoke contractions of limb muscles. Therefore, action potentials that contributed to the evoked compound potentials recorded in these horses arose, most likely, from afferent nerve fibers.

A method for quantification of serum total IgE concentration in dogs by use of an ELISA containing monoclonal mouse anti-canine IgE was developed. Microtitration plates were coated with monoclonal mouse anti-canine IgE. Test sera and reference serum dilutions were added, followed by biotinylated monoclonal mouse anti-canine IgE. Avidin-alkaline phosphatase conjugate was added, and color development was measured spectrophotometrically, using a microtitration plate reader. Quantitative results were obtained by assigning to a reference serum a value of 100 IgE units/ml. Absorbance values of unknown samples were converted into IgE units by comparison with a standard curve generated by measurement of reference serum dilutions. Intra- and interassay coefficients of variation were 5 and 7%, respectively, and assay sensitivity was 1 U/ml. The assay was used to establish a normal range for total IgE concentrations in 30 healthy dogs. Total IgE concentration in healthy dogs followed a skewed distribution and ranged from < 1 to 91.2 U/ml, with a geometric mean value of 7.1 U/ml. The IgE concentration was remarkably stable in serum samples subjected to 25 freeze/ thaw cycles or incubation at approximately 25 C (room temperature) for up to 10 days. Comparison of total IgE concentrations in 23 serum samples assayed by use of double-overlay radial immunodiffusion and ELISA yielded correlation coefficient of 0.94. Comparison of the reference serum standard curve with serial dilutions of a purified IgE solution of known concentration yielded a range of values for the IgE unit of 0.7 to 2.0 micrograms.

A relation exists between colloid osmotic pressure and serum total protein concentration; equations describing this relation have been used to determine a calculated value for colloid osmotic pressure. However, the relation between total protein concentration and colloid osmotic pressure is altered by the method used to measure protein and by changes in the ratio of concentrations of albumin (A) to globulin (G). We developed nomograms for estimating colloid osmotic pressure from A and G concentrations, using samples obtained from clinically normal animals and compared the accuracy of these nomograms with that of previously described equations relating colloid osmotic pressure to total protein concentration. For comparison, serum samples from canine (n = 106), equine (n = 79), feline (n = 24), and bovine (n = 27) patients admitted to the University of Georgia Veterinary Medical Teaching Hospital were used. Results indicated that nomograms based on protein concentration estimated by a refractometer generally were the least reliable. Although predictive nomograms, using total protein concentration determined by the biuret method, provided better results for serum samples, there was considerable variation between measured and calculated values for colloid osmotic pressure in all species studied. Calculated values for colloid osmotic pressure derived from A and G concentrations were most closely related to measured values for colloid osmotic pressure in dogs, horses, and cats. However, calculated values for colloid osmotic pressure differed from measured values by as much as 5 mm of Hg for some samples by each of the methods of estimation. These results indicate that, although calculated values for colloid osmotic pressure may be most accurate when variations in the A-to-G ratio are accounted for in the nomogram, none of the calculation methods provided a consistently accurate estimate of colloid osmotic pressure. For clinical patients, colloid osmotic pressure based on these nomograms cannot replace direct measurement.